2018-2019 年汛期小浪底水库排沙运用分析.

In the flood seasons of 2018 and 2019, the inflow of Xiaolangdi Reservoir was higher than before and it was the first time that the operation of low reservoir level, long duration,large discharge, and high sediment concentration was applied for two consecutive years, which effectively scoured the sediment in the reservoir area. This paper analyzed the influencing factor of sediment discharge and established the calculation formula of the reservoir sediment discharge ratio by the regression analysis method, based on the actual sediment discharge operation of the reservoir. The results point out that pondage, lowest water depth and inflow are most closely related to sediment discharging, with a high correlation above 0.80. The calculation formula for the sediment discharge ratio verified by the measured data can simulate the sediment discharge of the reservoir well. Based on the observation data of the topography of the reservoir dam area, the sediment scour and silting change in the dam area were analyzed, and it was proposed that the river bed gradient within 4.5 km of the reservoir area had been stabilized between 4.3‰ and 5.1‰ since 2014, under the influence by the discharge bottom hole. The lowest elevation of sediment deposition in front of the intake tower varies between 176 m and 181 m. On the right bank in front of the dam, the sediment deposition elevation gradually rises and the slope becomes steeper. Currently, a stable slope has not been formed. As the left bank in front of the dam is close to the mountain with a high slope and there is little sediment accumulation. [ABSTRACT FROM AUTHOR]